1. Field of the Invention
The present invention relates generally to clock generators and more specifically to a clock generator using complementary insulated gate field effect transistor inverters for producing a time delay.
2. Description of the Prior Art
In the field of clock generators or pulse-producing circuits, it is common to use time delay circuits and inverters in one or both parallel paths between the input and output logic. The composite circuit produces a pulse of a duration as a function of the time delays. In the prior art, the time delays are generally produced by resistor-capacitor circuits or by clocked inverters. The resistor-capacitor circuits increase the size and layout complexity and process steps of integrated circuits. The time delay of the clocked inverter is produced by the timing of the clock pulses. Though clock converters do produce an output pulse of a given width in response to a given input signal, it is not truly a clock circuit since it requires an external timing signal in addition to an input signal.
There exists a need for a clock producing or clock generator circuit wherein the circuit is self-contained and produces an output pulse in response to an input signal. With the advance of integrated circuits, it has also become important that the circuit take advantage of inherent design characteristics of the elements in the integrated circuit to reduce the number of additional circuit elements. It is known that complementary insulated gate field effect transistors (IGFET) inverters operate in a wide range of operating voltages and minimizes participation. Also, the use of parasitic capacitors to produce a time delay between stages of complementary IGFETs has been used in other circuit applications. The use of unbalanced or different resistivity devices in a complementary pair of IGFETs has also been used in other logic circuits.